1. Field of the Invention
This invention relates to an apparatus for punching and binding a stack of margin punched hole paper sheets where binding elements enter through the punched holes. More particularly the invention is directed to a binding apparatus with additional capabilities than that apparatus disclosed in the related application including a binding station for so-called Velobind.RTM. PVB binding strips (Personal VeloBinder). The PVB binding utilizes a front strip having a series of typically six projecting flexible studs which pass through a margin apertured (typically six holes) paper sheets stack and through a six hole back strip. The projecting ends of the studs are bent about 90.degree. into a series of six holding grooves on the backside of the back strip between the strip holes. U.S. Pat. Nos. 4,674,906 and 4,685,700 exemplify the PVB-type binding strips per se.
Additionally the invention relates to an improved mechanism for clamping an assemblage of binding strips and a paper sheets stack and an improved binding station utilizing a Douvry-type binding element (U.S. Pat. Nos. 1,970,285 and 2,257,714) in the apparatus of the related application.
In the related application it was contemplated that the dual or triple punch mechanisms disclosed would be used with a Douvry-type binding in one binding station and with a Velobind.RTM. binding of the cut-off and upset stud type in a second binding station. That earlier type of Velobind binding is seen in U.S. Pat. Nos. 4,354,783 and 4,369,013.
2. Related Art
A bending apparatus for bending the PVB-type of binding strips is seen in U.S. Pat. No. 4,906,157 where a pivoted lever arrangement moves a pair of blocks carrying rollers, with each block moving inward toward the center upon lever actuation to bend and snap the projecting ends of the flexible studs simultaneously into the back strip grooves. Other roller mechanisms have been proposed to bend the projecting end studs into the grooves. Initially in early commercialization, the bending of the stud projecting ends was accomplished by manual bending.
Further it has been contemplated that a pressure bar may be employed for compressing a pair of binding strips with a paper sheets stack therebetween as exemplified by U.S. Pat. No. 4,354,783. In other devices a vertically movable motor-driven pressure bar is provided driven through racks and rollers fitting in side plate slots. These devices also include a stud bending mechanism having drum cams, transverse rods, and a pair of carriages with rollers which bend the projecting stud ends so that they snap into the strip grooves. This is seen in U.S. Pat. No. 5,015,138 issued May 14, 1991.
In another stud bending machine U.S. Pat. No. 5,017,071 issued May 21, 1991, provision is made for moving and clamping female strips and bringing them into contact with a paper sheets stack. A male strip with the projecting studs is moved upwardly to pass through the stacked paper apertures and the holes in the female strip. A crank shaft is turned and legs of a closer plate bends and depresses the projecting stud portions. A carriage is then moved to its loading position for the next cycle of operation.
One of the difficulties of the above machines is the care one must take to avoid improper loading of the strips. Such improper loading may damage the machine if the female strip is placed upside down and there is no downwardly-facing series of grooves to accept the bent studs ends. In such event the bent studs would have no space to move and the machine would be subjected to stresses and deformation which may cause permanent damage. Further, it is clear that the prior art stud bending machines are independent stand-alone items and have no capability of punching holes in a stack of paper sheets nor any capability of providing for other binding elements such as a Douvry-type binding:
U.S. Pat. No. 3,967,336 (Cutter) shows a punch lever for shifting and operating a Douvry-type binding mechanism. U.S. Pat. No. 3,122,761 shows a rotory lever for operation of a hook plate containing diagonal slots.